* Notice and status bar improvements
Status bar problems added in the same pass got the same `Date.now()` id and overwrote each other, so usually only one showed. Messages now fall back to their text as the id. The desktop status bar shows the most severe message with a count of the rest that opens a popover listing all of them, and the mobile drawer stacks them vertically instead of placing them side by side.
Dismissing a notice hid it for good, so a detector that restarted again after a dismissal was never shown. Dismiss is replaced by acknowledge, which hides a notice until it happens again, and mute, which hides it permanently. Kinds that never repeat (config and stream checks, the update notice) can only be muted. `reopen_at_count` is removed since acknowledge covers the failed login case.
* move camera CPU warnings to notices
High ffmpeg and detect CPU warnings sat in the status bar with no way to dismiss them. They're now `ffmpeg_high_cpu` and `detect_high_cpu` notices, raised per episode by the same tracker as skipped detections. Also stop failed login attempts held from before an acknowledgement from reopening the notice.
* fix mypy and handle missing cpu stats in notices
